This section provides background information related to the present disclosure which is not necessarily prior art. Colloidal crystal assemblies are used for various applications, including in sensors, optics, and communications, by way of non-limiting example. Colloid crystal assemblies are important for various micro-engineering applications, like the design of optical and optoelectronic components (e.g., polarizers, waveguides, filters, and photonic circuits), nanoporous templates for applications in separation, filtration, and sensing, and as photonic transducers of chemical and biological signals. However, the ability to control organization and assembly of colloidal crystals is important to the production and utilization of various materials with functional optical, mechanical, and/or conductive properties.
While colloid particles may self-assemble into crystals naturally, such processes are slow (e.g., limited by their slow kinetics) and lack the ability to manipulate and control the structures in space and time. Conventional directed assembly processes for organizing and assembling colloids afford more control and partially address the problem of self-assembly, with the use of gravitational, electrical and/or magnetic fields or templating, but such processes are limited by their confinement to two-dimensional (2D) colloid assemblies and lack of reconfigurability or reversibility due to the reliance on templates and fixed surface features. Recent efforts to produce reconfigurable colloidal assemblies have included holographic optical tweezers, optically tunable electrophoretic and electrokinetic assemblies, photoresponsive colloids and DNA directed assembly.
However, such conventional colloid assembly methods have been limited by their requirement for complex optics (e.g., holographic optical tweezers), confinement to 2D assemblies (e.g., directed assembly by DNA-linked colloids), or lack of reversibility (e.g., photoresponsive colloids) and spatial reconfigurability due to fixed templates and surface features (e.g., dielectrophoresis). A template-free method also providing the ability to reversibly control and reconfigure colloidal crystals simultaneously in three-dimensional space and time, without any need for electrode pairs, would be particularly advantageous. Likewise, it would be desirable for various applications, including adaptive optics or reconfigurable circuit elements with conductive functionalities, to provide devices and methods of assembly in which three-dimensional (3D) colloidal crystals could not only be reversibly switched on and off in time, but can also be simultaneously controlled and manipulated in space, on the micrometer scale, without the restriction of fixed surface features such as electrodes and templates.